Blackmantle

Choose a 15-foot radius area within range. Any living creature within the area must make a Constitution saving throw. On a failed save, the creature is outlined with a dark aura and it can’t benefit from healing or regeneration for the duration. In addition, the creature can’t benefit from invisibility whilst affected by this spell. An affected creature can make another saving throw at the end of each of its turns, ending the spell’s effect on it with a success.